Note: If you click either of the small images, you’ll get one that is 800 pixels across. I’ve also provided links to larger versions for those who are interested.
An early attempt at copying the Black Ding glaze, starting from the analysis in Chinese Glazes. This bowl was fired to cone 10.5, in reduction, in Edwin Gould’s gas kiln, in Columbia, Maryland. Despite the relatively high firing temperature, it is teadusty and underfired. Nigel Wood’s analysis has 16.7% Alumina, which seems relatively high for a cone 9 glaze, and this bowl helped me decide that I should decrease the amount of clay in my formula.
1768 x 1704 pixels
Vase, Helios porcelain (from Highwater); “China Black” glaze, fired to cone 9 in an electric kiln, with a hold at peak temperature. The piece is just under 4" tall.
There is a slight difference between this glaze and the recipe in the article -- I ran out of high-purity RIO while mixing this batch, and used 84% pure RIO to make up the balance. Either way, the glaze is quite well behaved, and I routinely apply it to within a millimeter of the foot. There is, of course, no way to know in advance how it will behave on your clay in your kiln, so I must repeat the Glaze Tweak creed: test, test, test!
1680 x 2256 pixels
Here is the recipe, with Seger and Weight Percentage breakdowns:
Joss Research “China Black” v1.0 (Cone 9 oxidation) G-200 Feldspar 38 Sapphire Kaolin 10 Silica 25 Whiting 15 Magnesium Carbonate 3 Red Iron Oxide (98%) 9 ========================== Seger Numbers: K2O 0.163 Na2O 0.082 CaO 0.626 MgO 0.128 Al2O3 0.432 SiO2 3.628 Fe2O3 0.227 TiO2 0.007 (SiO2:Al2O3 ratio 8.4) ========================= Weight Percentages: SiO2 60.62 Al2O3 12.25 K2O 4.27 Na2O 1.41 CaO 9.77 MgO 1.44 Fe2O3 10.08 TiO2 0.16
(08 December, 2004)
I am working on a slightly more traditional version of
this glaze, using Redart Clay as the primary ingredient.
If this pans out, I’ll put at least one recipe and a
Note: The photos were taken on September 25th, 2004, with
a Canon G3 camera, in daylight. The camera records 2272x1704
pixels, the common 4-megapixel format. I chose the G3 by
comparing digital camera reviews and discovering that it had
slightly better resolution than almost all of the other
cameras in its price/performance range, and that its
specifications were, in general, quite good. It also offered
focus bracketing, which was not available on any other
ordinary digital camera at the time, and it has a fully
manual mode. The digital camera world, however, is
constantly changing, and I don’t know the current state of
the art. (I did recently notice a very good review of the
Canon G6, though.)
“Red Tenmoku”, another glaze project
To the Studio Potter
My email address is email@example.com, where a is jon and b=joss.
My phone number is +1 240 604 4495.
Last modified: Fri Dec 22 19:52:49 EST 2006